Cytomegalovirus retinitis after low-dose intravitreous triamcinolone acetonide in an immunocompetent patient: a warning for the widespread use of intravitreous corticosteroids.

We report the case of an immunocompetent 78-year-old woman who developed cytomegalovirus (CMV) retinitis after a single intravitreous injection of triamcinolone acetonide (IVTA). Review of medical records. The patient with macular edema secondary to branch retinal vein occlusion developed peripheral retinitis with hemorrhagic and inflammatory vascular sheathing 3 months after IVTA. A presumptive diagnosis of viral retinitis was confirmed by polymerase chain reaction (PCR) of the aqueous humor tap. The PCR test was positive for CMV DNA. The patient slowly responded to intravenous ganciclovir and oral valganciclovir. After therapeutic vitrectomy for intercurrent vitreous hemorrhage, and while still under treatment, the retinitis resolved completely with final visual acuity of 20/25. CMV retinitis can occur after local immunosuppression with IVTA in an immunocompetent patient with no other systemic risk factors.

Intact satellite cells lead to remarkable protection against Smn gene defect in differentiated skeletal muscle.

Deletion of murine Smn exon 7, the most frequent mutation found in spinal muscular atrophy, has been directed to either both satellite cells, the muscle progenitor cells and fused myotubes, or fused myotubes only. When satellite cells were mutated, mutant mice develop severe myopathic process, progressive motor paralysis, and early death at 1 mo of age (severe mutant). Impaired muscle regeneration of severe mutants correlated with defect of myogenic precursor cells both in vitro and in vivo. In contrast, when satellite cells remained intact, mutant mice develop similar myopathic process but exhibit mild phenotype with median survival of 8 mo and motor performance similar to that of controls (mild mutant). High proportion of regenerating myofibers expressing SMN was observed in mild mutants compensating for progressive loss of mature myofibers within the first 6 mo of age. Then, in spite of normal contractile properties of myofibers, mild mutants develop reduction of muscle force and mass. Progressive decline of muscle regeneration process was no more able to counterbalance muscle degeneration leading to dramatic loss of myofibers. These data indicate that intact satellite cells remarkably improve the survival and motor performance of mutant mice suffering from chronic myopathy, and suggest a limited potential of satellite cells to regenerate skeletal muscle.